Reflectivity and Dielectric Properties

1) a very high reflectivity R at low photon energies (E 2 eV), which is typical of metals, 

2) a deep minimum R in near 2 to 3 eV caused by the onset of plasma oscillations excited in the conduction band (longitudinal excitation mode), and as the photon energy increases, 

3) by a broad reflectivity maximum which is associated with electronic interband transitions from the 4p(Se) valence band to the 5d(M) conduction band. 

The following table lists the spectral positions of Rmm. the energy loss function (ELF) maximum, and coj, and gives the high-frequency optical permeability e that characterizes the material in the absence of the conduction electrons for single crystals (c), powders (p), sintered samples (s), dispersed powders (d.p.), and films (f)  

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The variation of transmission, reflection and dielectric properties with doping level and temperature have been investigated in the case of polypyrrole [68,69]. The heterogeneous nature of polyaniline ( metallic islands ) has been used in order to explain experimental results [50] and the tri-dimensional nature of metallic states has been examined [70], Polyaniline has also been characterised in the low-frequency range by impedance measurement [71],... 

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